Well, regardless of caching and special ORM, doing 11K peak sql qps on 15% cpu load, is remarkable. They did a great job optimizing the database and access.
They probably also save a lot on ops team - running a single sql server with a failover is well-understood, error-resistant and covered in vendor's guides/best practices.
They probably also save a lot on ops team - running a single sql server with a failover is well-understood, error-resistant and covered in vendor's guides/best practices.